Weight adjuster for scales



Jan. 19, 1960 w. E. WlGHAM WEIGHT ADJUSTER FOR SCALES 4 Sheets-Sheet 1Filed May 27, 1953 INVENTOR. w. Eiw IG HAM BY M014.

' AT TORNEYS Jan. 19, 1960 w. E. WIGHAM WEIGHT ADJUSTER FOR SCALES FiledMay 27. 1953 4 Sheets-Sheet 2 INVENTOR.

W E WIGHAM ATTORNEYS Jan. 19, 1960 w. E. WIGHAM WEIGHT ADJUSTER FORSCALES Filed May 27, 1955 4 Sheets-Sheet 3 NEED mzmmrkm Jan. 19, 1960 w.E. WIGHAM WEIGHT ADJUSTER FOR SCALES 4 Sheets-Sheet 4 Filed May 2'7,1953 TO ELECTRIC SOURCE IOI FIG. 4.

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INVENTOR. w E WIGHAM BY /MM WW ATTORNEYS United States Patent f2,921,767 WEIGHT ADJUSTER FOR SCALES William E. Wigham, Berger, Tex.,assignor to Phillips Petroleum Company, a corporation of Delaware.Application May 27, 1953, Serial No. 357,868 g 6 Claims. (Cl. 249-14)This invention relates to automatic scales. In one aspect it relates toan apparatus for facilitating the accurate adjustment of the automaticscale so as'to increase or decrease the total weight by a controlled andpredetermined'amount. In another aspect this invention relates to animproved meansfor accurately weighing the component parts of a mixturecomposed of definite amounts or different materials and a method forquickly and accurately changing the quantity of any or all of thesecomponent parts. In a more specific aspect it relates to an apparatusfor accurately changing the Weight of carbon blackslurry and rubberlatex weighed on automatic scales and dumped into a mixing tank priorto'co'agulation of the carbon black loaded rubber.

Inthe manufacture of rubber, carbon black is added to the latex indefinite, predetermined amounts and is thoroughly mixed with the latexprior to the coagulation step wherein the rubber crumbs are formed. Inthemanufactureof synthetic rubber, the monomers which form the rubber,for example butadiene and styrene, are polymerized in aqueous emulsionand after the unreacted butadione and styrene are removed by steamstripping the latex is recovered and stored prior to the addition of thecarbon black. The carbon black is dispersed in water, usually .with theaid of a dispersing agent, and such carbon black slurry is stored priorto being incorporated into the rubber latex. The latex and carbon blackslurry are weighed in predetermined amounts on separate automaticloading and dumping scales and the weighing hoppers of both scales aresimultaneously'dumped into amixing'tank when both hoppers have beenfilled with the required amounts of materials. i

The amount offca'rbon black incorporated in a latex must be controlledwithin very close limits and when the nature of the carbon black slurryor the latex varies because of the changes in the total solids content,differences in the, characteristics of the carbon black being used,errors in the determination of the total solids content of the latex orthe carbonblack slurry and changes in other variables, it is necessaryto make adjustments in theamount of carbon blackand latex weighed on theautomatic Scales in order to prevent the production ofoff-specificationrub- .ber. Even though it may be known that a definite increase in theamount of carbon black is required, for example an increase of pounds ofcarbon black slurry per loading, it is difllicul't to make suchadjustment in weight immediately since the scale must be adjustedusually over several loadings in order to arrive at the proper weightandduring the time of such adjustments elf-specification rubber may beproduced. The feed to the dumping hopper on the scale platform isstopped by operation of a mercury-magnetic switch actuated by a magnetsecured to the scale platform so that the switch is operated when theplatform is moved downwardly. The weight adjustment is made by turning,a"knob on a threaded rod so as to raise or lower the mercury switch andthus to adjust its position with relation to the magnet.

2,921,767 Patented Jan. 19, 1960 It is an object of this invention toprovide an apparatus for quickly and accurately changing the amount ofmaterial weighed on an automatic scale by a predetermined amount.

It is another object to provide a means for accurately weighing thecomponent parts which are to form a mixture and to change the ratio ofthese component parts by a predetermined amount.

It is still another object of this invention to provide a means forweighing the carbon black slurry and latex to form a mixture so thataccurately controlled amounts of the carbon black slurry and the latexare simultaneously dumped from automatic scale hoppers.

It is still another object to provide an apparatus for simultaneouslyweighing accurately controlled amounts of carbonblack slurry and latexon separate scales and simultaneously dumping these materials when thelast hopper is filled.

Other objects and advantages will be apparent to one skilled in the artupon reading this disclosure and the attached drawing wherein:

Figure 1 is a schematic drawing of the weight adjuster device;

Figure 2 is a schematic drawing of a pair of automatic scales showingthe wiring circuits;

Figure 3 is a schematic flow sheet showing the steps of a syntheticrubber manufacturing process wherein this invention is employed;

Figure 4 is a schematic representation of one modification of the weightadjuster device of Figure 1; and

Figure 5 is a schematic representation of another modification of theweight adjuster device of Figure 1.

onemodification of this invention.

In a typical synthetic rubber manufacture, eight or more scales will beused to weigh the carbon black slurry and latex which go to make up thecarbon black loaded mixture. These weights will require changes at leasttwo or three times per 8-hour shift as the carbon black slurry and latexfeeds are changed from one storage tank to another. Additionaladjustments are required whenever tests on the finished rubber indicateimproper proportioning of the latex or carbon black slurry. It isnecessary to make these Weighing adjustments by turning a knob on thescale so as to either raise or lower the mercury-magnetic switch whichcompletes an electrical circuit so as to stop the feed to'th e' hopper.Since one turn of the knob will not cause a constant amount of change inweight, it normally requires 3 or 4 adjustments before the desiredoperation is obtained. With eight or more scales to adjust, this becomesatime consuming operation and results in considerable off-specificationrubber being produced. In one plant, the ofl-specification rubberproduced in one year because of improper carbon black loading wasapproxi mately 358,000 pounds. This elf-specification rubber representsa loss of several thousand dollars.

f I have invented an apparatus which, when attached to an automaticscale, will enable one to change the weighings by a predetermined amountquickly and accurately. The apparatus of my invention comprises acalibrated indicating device attached by a positive linkage to the rodwhich raises and lowers the mercury-magnetic switch so as to positivelyindicate the amount of change in the weighings. I The device isadvantageously calibrated in pounds although it can be calibrated inother units such as percent, etc.

The invention will now be explained with reference to the drawing. InFigure 1 the weight adjuster- 34 is shown mounted upon the dial of anautomatic scale 11. Thread ed rod 12 raises or lowers themercury-magneticswitch 13 by turning the knob 14 so as to cause rod 12to travel through the threaded top of cylinder 15. Magnet 16 opensthem'ercury-magnetic switch when the platform 10 of the scale is inraised position'and the hopper is being sup- 7 again tightened;

- Cylinder 15 is secured Spool 17 isthreaded so as tofit the threadedrod 12 and is secured from movement by the thumb screw 18, Pointer 19fits in the slot 21 of spool 17 and indicates the amount of change in.weight on the dial 22,,

The pointer is hinged at 23' and the pointer is held againstthe upperside of slot 21 in spool 17 by the spring 24.. The spring 24 preventsany slack in the mechanism so that the pointer responds to the slightestmovement of knob 14. The instrument is initially'adjusted by "loosen ingthumb screw 18 and centering pointer 19 in dial 22 without turning rod12 after which thumb screw 18 is to'the framework of the scale asindicated at 2S. Bushings indicated at 26 aresecured to rod 12 so as toallow arm 27 of switch 13 to travel vertically in slot 28 of cylinder 15as the rod 12 is moved vertically through the threaded top of cylinder 1In Figure 2 a latex, weighing hopper is indicated at L and a carbonslurry weighing hopper is indicatedatB and both the latex and carbonblack hoppers dump into a mixing tank C. The latex scale is indicated at11, the magnet 16 actuates the mercury-magnetic fswitch indicated at:13. The indicating weight adjuster of this ininvention are employed Onthese scales.

steam stripping zone 75 where the styrene is removed as overheadproduct. The-latex is recovered as bottom product from the steamstripping operation and is passed to storage tank 76. Carbon black isdispersed in water in a mixing zone 77 and a dispersing agent is'usuallyadded at this point (not shown). The carbon black slurry 'is then passedto storage tank 78. Latex and carbon black slurry are drawn from storagecontainers 76 and 78, weighed in the hoppers 79 and 81 of automaticscales 11 and 11', and the weighings of the .tWO' scales aresimultaneously dumped from the hoppers into a mixing tank 84. The weightadjusters 34 -34' of this In the mixing tank 84 the carbon black andlatex are thoroughly mixed and then passed to a coagulation tank 85where the rubber, loaded'with carbon black is coagulated from the latexby the addition of acid, ammonium sulfate, or other coagulant. Thecoagulated rubber crumbs overflow from the coagulation tank 85 to aleach tank 86 where the crumbs are thoroughly washed with water. Thecrumbs overflow from the leach tank over a shaker screen 87 to a arotary vacuum filter SSwhe re the major portion of the plete removal ofmoisture, and then to a baler 911where the crumbs are bound into balesas the product of the vention which raises or lowers switch 13 is shownat 14.

V Scale11 is regulated by an indicating weightadjuster 14' identical tothat employed upon scale 11;. The met cury-rnagnetic switch 13 of thelatex scale 11 is connected to .electrical source 36 and to a solenoidvalve 42 on secured from vertical movement on rod 12a.

the latex feed. line 43 to the latex hopper L. The sole:

noid valve 42 is adapted to beclosed byclosureof' switch .13. Themercury-magnetic switch-13' is .connected to electrical source Y36 andto solenoid valve 44 valve 44 iS-adapted to be closedtby closureoffswitch 13 Closure of both switches .35 and 37 completesanxelectrical'circuit to motor 46 which operates a time cycle device soasto cause cam 47 to close vswitch 48 so as to complete a circuitopening solenoid valves-Q49 and '51.

Thus when both hoppers L and B are filled, they are 1 a the carbon blackslurry feejd line'45. The solenoid water is removed, and then to a drier89 for more comrubber manufacturing process.

Figure 4 is a schematic representation of a modification of the weightadjuster device of Figure 1 and is shown mounted upon the dial of anautomatic scale l la. Rod 12a is threaded through the scale 11a and isoperatively connected to magnet 16a by lever 101 pivoted at 102. ISleeve 105 is free to rotate upon rod 12a but is M ne 1 6a slidesvertically on rod 103 and tension ismaintained on the linkage by coilspring 104. Inthis embodiment the positions of the magnet 16a and theswitch'13 a have been reversed from that shown in Figure 1. Thus themagnet is'maintained in a stationary position and the mercury switch isattached to the platform 10a. Adjustments in weighings are made byvertical displacement ofthemagnet. i I i ,FigureS shows another meansofactuating the pointer of theweight adjusting device. In thismodification spool 17 of Figure 1 is replaced by gear wheel 17b whichdis? places rack 110vertical1y on'guide rod 111 so as to rotatepointer'19b about pivot23b. Spring 24b maintains tension o'nrack .110 soas to eliminate slack or play;

The employment of the improved means for weighing carbon black slurryand latex ofthis invention hasprac In.order to prevent the additlon ofmore carbon black slurry andlatex than the mixing tank rC-can, hold, aliquid level control having a float 5 6 breaks contacts 57, 58, 5S}, and61 when the level is above a predetermined point. The breaking of thesecontacts holds all of the circuits pen and stops all operations exceptthe dumping .of

. hoppers L andB.

I Figure 3 is a schematic flow sheetgof one' process for thedmanufactureof synthetic rubber. In process butadien and sty ar po y er ze a polymerz .tion zone'7l; passed ,to a blow-down zone 72 where some but'ad enelisrecovered from vent Z the te aflashzqn Hwhqreflie butadi neli lflas ero. as rare .the .t a

tically eliminated off-specification rubber resulting from impropercarbon black loading. Furthermore, the time required for the operator tomake the weight'adjustment has been greatly minimized leaving moretirnefor other duties which has resulted in a general improvement operations.Additional advantages will be apparent to those skilled inthe art fromaconsiderationof this dis.- closure and theac companying drawing.

Reasonable variations and modifications are possible within the' fsco'peof the disclosure of this invention, the essence of which is theprovision of an apparatus for accurately predetermining the amount ofchange made in adjusting the weight on automatic scales and an' improvedmeans for operating automatic scales wherein the .various componentswhich form a predeterminedmixture areaccurately weighed and maintainedin a definite proportion. I V

.I claim:

1.3 1 l llqmaticscalecomprising;a dial,a platforrn;

to the movement of a magnet actuated by the scale platform theimprovement which comprises a threaded rod; a threaded bushing attachedto said'scale and engaging said threads of said rod; means operativelyconnecting said rod and said switch; a knob for turning said rod so asto adjust said switch vertically with respect to said magnet; a spoolaxially threaded on said rod and having means for rigidly securing saidspool to said rod, said spool having a recessed portion; a pointerhaving a pivoted' connectionintermediate its ends and having one endadapted for sliding contact witlr the recessed portion of said. spool; acalibrated second dial adjacent thecfree end of saidpointer; and aspring operatively connected to said pointed so as to urge the pointerinto contact with one side of said recess of said spool.

2. An apparatus for automatically weighing latex and carbon black slurryin accurate and predetermined amounts and simultaneously dumping saidlatex and said carbon black when both weighings are completed whichcomprises 'a first scale comprising a dial, a platform, and meansconnecting said dial and said platform so as to indicate on said dialthe weight of material supplied to said platform; a latex hopperdisposed upon said first scale platform and having a normally closedsolenoid outlet valve; a latex feed tank; a latex feed line connected tosaid latex tank for supplying said latex hopper; a solenoid valve insaid latex feed line; a second scale having a platform; a carbon blackslurry hopper disposed upon said second scale platform and having anormally closed solenoid outlet valve; a carbon black slurry feed tank;a slurry feed line connected to said slurry tank for supplying saidslurry hopper; a solenoid valve in said slurry feed line; a tank adaptedso as to receive the contents of both said hoppers; a first magnetadapted to move in concert with the latex weighing platform; a secondmagnet adapted to move in concert with said carbon black weighingplatform; a first mercury-magnetic switch operated by said first magnetwhen said latex hopper depresses the weighing platform; means forpositively adjusting the weighing of said latex scale a predeterminedamount by raising or lowering said first switch; means for indicatingthe vertical displacement of said first switch in terms of the weight ofmaterial supplied to the plat form; a second mercury-magnetic switchoperated by said second magnet when said carbon black hopper depressesthe slurry weighing platform; means for positively adjusting theweighing of said carbon black scale a predetermined amount by raising orlowering said second switch; means for indicating the verticaldisplacement of said second switch in terms of the weight of materialsupplied to said platform; a first circuit adapted to close the solenoidvalve in the latex feed line to the latex hopper when said first switchis closed; the second circuit adapted to close a solenoid valve in thecarbon black slurry feed line to the carbon black slurry hopper whensaid second switch is closed; a third switch connected by a linkage tosaid first switch; a fourth switch connected by a linkage to said secondswitch; a third circuit containing a motor and completed by closing saidthird switch and said fourth switch; a first timing cam operated by saidmotor; a fourth circuit containing means for opening the outlet valvesof said latex hopper and said carbon'black hopper; a switch operated bysaid first cam so as to complete said fourth circuit for a predeterminedtime; a second timing cam operated by said motor; a fifth circuitcontaining means for reopening said first, second, third, and fourthswitches after a predetermined time following the operation of saidfirst cam; a switch operated by said second cam so as to complete saidfifth circuit; and means for opening all of the circuits except saidfourth circuit when the liquid level of the tank into which said hoppersare dumped is above a predetermined level.

3. In an automatic scale comprising a dial and a weighing platformsupported upon a scale frame, a hopper 7 of said magnet in terms of theweight of positioned on said platform and means for connecting said dialand saidv platform to indicate on said dial the weight of materialssupplied to said hopper, apparatus comprising'a magnet rigidly attachedto theweighing platform; a mercury-magnetic switch positioned on saidscale so as to be operated by said magnet when the weighing platform isdepressed a predetermined amount; means for vertically displacing saidswitch with respect to said magnet; means for indicating the amount ofdisplacement of said switch in terms of the weight of materials suppliedto said hopper; conduit means for supplying materials to said hopper; aloading valve positioned in said conduit means; and a circuit includinga source of electrical energy operatively connected to said valve and tosaid switch so as to operate said valve upon closing of said switch.

4. In an automatic scale comprising a dial, a platform, means connectingsaid platform and said dial so as to indicate on said dial the weight ofmaterial supplied to said platform, and a valved conduit means forsupplying material to said platform, the improvement which comprises amagnet rigidly attached to said platform; a vertical, threaded rod; athreaded bushing secured to said scale and threadably engaging said rod;a sleeve positioned around said rod; means for preventing verticalmovement of said sleeve on said rod; means for preventing rotation ofsaid sleeve; a mercury-magnetic switch secured to said sleeve in closeproximity to said magnet and maintained in open position by said magnetwhen said platform is in raised position; means for rotating said rod;means for indicating the vertical displacement of said rod in terms ofthe weight of material supplied to said platform; and an electricalcircuit, including means to close said valved conduit and including saidmercury-magnetic switch, which is completed by closing said switch whenthe material supplied to said platform depresses said platform therebyremoving said magnet from close proximity to said switch.

5. In an automatic scale comprising a dial, a platform, means connectingsaid dial and said platform so as to indicate on said dial the weight ofmaterial supplied to said platform, a conduit for supplying material tosaid platform, and a valve in said conduit, the improvement comprising amagnet rigidly attached to said platform; a vertical rod adapted forvertical displacement with reference to said magnet; a mercury-magneticswitch positioned so as to be maintained in open position by saidmagnet, operatively connected to said rod so as to be verticallydisplaced by said rod; means for closing said valve; an electricalcircuit, including said switch and said means for closing said valve,which is completed by closing said switch when said platform isdepressed so as to remove said magnet from proximity with said switch; aspool connected to said rod; a pointer operatively connected to saidspool; resilient means urging said pointer in contact with said spool;and a second dial adjacent said pointer for indicating changes in thevertical position of said switch.

o. In an automatic scale comprising a dial and a werg ng platformsupported upon a scale frame, a hopper positioned on said platform andmeans for connecting said dial and said platform to indicate on saiddial the weight of materials supplied to said hopper, apparatuscomprising a mercury-magnetic switch rigidly attached to the weighingplatform; a magnet positioned on said scale so as to operate said switchwhen the weighing platform is depressed a predetermined amount; meansfor vertically displacing said magnet with respect to said switch; meansfor indicating the amount of displacement materials supplied to saidhopper; conduit means for supplying materials to said hopper; a loadingvalve positioned in said conduit means; and a circuit including a sourceof electrical energy operatively connected to said valve and to sai .swih- References Cited in the file of this patent UNITED STATES PATENTS VNewman -Q-Oet. 20, 1903 ValoiS Junef29, 1 915 Kellerstedt Nov. 18, 19 24Hurt June 4, 1 929 Michener an. ,8, 1 935 Brady .14, 1936 Hall-"'?-".--,'-+'r--r-r'-:

Bu t i Feb: 29 .19 4 pr- ,19

. art son 1? my 3,1951 Miller May"1;2 ,;;1953 Weckerly O ct 20, 1953 SaDec, 2 195 My ti g ;,--:-,-f-1--+ -'M.aY 2. 5

FOREIGN PATENTS v 7 f UNITED STATES PATENT OFFICE CERTIFICATE OFCORRECTION Patent No, 2,921 767 January 19 1960 William E. Wigham It isherebfi certified that error appears in the -printed specification ofthe above numbered patent requiring correction and that the said LettersPatent should read as corrected below.

Column 5 line 14,, for "pointed" read pointer line 53 for "the second"read a second line 54 for "a solenoid" read the solenoid Signed andsealed this 16th day ofAugust 1960.

(SEAL) Attest:

KARL H. AXLINE ROBERT C. WATSON Commissioner of Patents Attesting()fiicer UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PatentNo, 2. 921 76? January l9 1960 William E. Wigham s in the-printedspecification It is hereby certified that error appear tion and that thesaid Letters of the above numbered patent requiring correc Patent shouldread as corrected below.

Column 5 line 14, for pointed" read pointer line 53 for "the second reada second line 54 for a solenoid" read the solenoid Signed and sealedthis 16th day of August 1960.

(SEAL) Attest:

KARL H. AXLINE Attesting Ofi lcer ROBERT C. WATSON Commissioner ofPatents

